replace dict data structures with dataframes in pandas

[HongPong]

revise the enrichment functions to use dataframes instead of dicts. the dataframes can still be exported as CSVs but we can more towards xslx for a better packing of different tables into one file that is easier to manage.

[HongPong]

was just informed of polars in #14 so let use that imo seems better at a glance, more modern . https://pola.rs/

[johnseekins]

#23 shows how we could start a migration to dataframes, but when using them internally, they function very similarly to dictionaries with the qualifier that it may actually complicate some steps (e.g. .get() doesn't exist in dataframes as you'd expect) because dataframes are columnar in form rather than row-based.

I'm not sure how much benefit we get from maintaining our internal representations as dataframes. But we certainly could explore it.

[HongPong]

do you think we should merge #23 or is it more of an example idea? i am open to whatever but was not sure if we should.